samsa

silica and moulding
sands association

Silca uses

Ceramics

Silica is important in several classes of ceramic;

Refractories:

Silica is used partly because of its abundance, but mainly due to its important properties of relatively high melting temperatures of around 1700 °C and ability to withstand high pressures with good dimensional stability at high temperatures when formed into a brick. These properties making such bricks ideal for the construction of both furnace superstructures and crowns.

Technical Ceramics:

Silica sand is heated to 2000 °C to produce fused silica, an important material with excellent thermal shock resistance, near zero thermal expansion and good mechanical properties at high temperatures; making it ideally suited to applications such as conveyer rollers, crucibles and firing supports in the high temperature industries such as glass and metals production.

By heating silica sand and carbon in the form of coke in an electric resistance furnace, Silicon Carbide is produced.

2SiO2 + 3C + heat → 2SiC + CO (gas)

Depending on its purity, silicon carbide has a wide range of uses due to its key properties of being very hard (9.1 on Mohs hardness scale), resistance to heat (decomposes at 2700 °C) and high thermal conductivity; including Abrasives and cutting tools, structural components, refractories and semi-conductors.

Whitewares:

Most clay based ceramics such as tableware, cookware, wall and floor tiles, pottery products and sanitaryware, contain silica along with feldspar and the clay as the three main components. The amount of silica varies considerably depending on the final properties of the article but is added to help retain the structure and shape of the article during processing and also, due to the glass forming properties of silica, produce the vitreous matrix that binds the ceramic together..